1. Field of the Invention
The present invention relates to a data reproduction method and a data reproduction apparatus. It, particularly, relates to a data reproduction method and data reproduction apparatus wherein audio data having a specific sampling frequency is recorded on a recording medium and the audio data is reproduced from the recording medium.
2. Description of Related Art
Conventionally, there has been known a digital video tape recorder in which video data and audio data are recorded on inclined tracks of a magnetic tape with the video data and the audio data being corresponded to each other. In this type of digital video tape recorder, there has been conceived that video data having a field frequency of 59.94 Hz is recorded after the number of items of sampled audio data having a sampling frequency of 48 kHz for each one frame period has been converted from 1602 (this number corresponds to the sampling frequency of 48 kHz) to 1600 (this number corresponds to the sampling frequency of 47.952 kHz) by a rate converter.
When audio data is recorded as in the manner described above if video data is reproduced at a field frequency of 59.94 Hz in the reproduction, the video data is output after the number of items of the sampled audio data that has been reproduced for each one frame period has been converted from 1600 (this number corresponds to the sampling frequency of 47.952 kHz) to 1602 (this number corresponds to the sampling frequency of 48 kHz) by the rate converter.
On the other hand, in a compatibility reproduction in which the video data is reproduced at a field frequency of 60 Hz in the reproduction, the video data is output with the number of items of the sampled audio data that has been reproduced for each one frame being kept at 1600 (this number corresponds to the sampling frequency of 48 kHz) without making any conversion.
According to this case, in order to reproduce the video data in the compatibility reproduction at a field frequency of 60 Hz, the data is recorded after the number of items of the sampled audio data for each one frame period has been converted from 1602 to 1600 by a rate converter and, when the data is reproduced in a normal reproduction at a field frequency of 59.94 Hz, the number of items of the sampled audio data for each one frame period is converted from 1600 to 1602. This causes a problem such that the reduction in the number of items of sampled data at the time of recording the audio data results in bandwidth limitation and filter rounding error in the rate converter, thereby deteriorating into sound quality.
An objective of the present invention is to present a data reproduction method and a data reproduction apparatus by which a compatibility reproduction is allowed without inducing deterioration in sound quality if a normal reproduction is performed.